Stability of the zwitterionic liquid butyl-methyl-imidazol-2-ylidene borane

Modification of the C2 position of the standard 1-butyl-3-methyl imidazolium cation by a borohydride group leads to a zwitterionic liquid (ZIL). The resulting imidazol-2-ylidene borane ZIL is liquid at room temperature. Dynamic viscosity as well as thermal and electrochemical stability are investigated. Thermal decomposition follows a similar pathway as in comparable imidazolium ionic liquids. The surprisingly low viscosity and good reductive stability make it a promising candidate for electrochemical applications

Halogen free 1,2,3- and 1,2,4-triazolide based ionic liquids : synthesis and properties

Triazoles have been successfully used as building blocks to create "fully organic" ILs featuring on both sides organic ions, i.e., 1,2,3- or 1,2,4-triazolide anions and 1,2,4-triazolium or imidazolium cations. Glass transition temperatures, densities and viscosities of these ILs were determined. Their electrochemical and thermal stability, and also conductivity, are higher than those for known ILs

Evidence for short range orbital order in paramagnetic insulating (Al,V)_2O_3

The local structure of (Al_0.06V_0.94)_2O_3 in the paramagnetic insulating (PI) and antiferromagnetically ordered insulating (AFI) phase has been investigated using hard and soft x-ray absorption techniques. It is shown that: 1) on a local scale, the symmetry of the vanadium sites in both the PI and the AFI phase is the same; and 2) the vanadium 3d - oxygen 2p hybridization, as gauged by the oxygen 1s absorption edge, is the same for both phases, but distinctly different from the paramagnetic metallic phase of pure V_2O_3. These findings can be understood in the context of a recently proposed model which relates the long range monoclinic distortion of the antiferromagnetically ordered state to orbital ordering, if orbital short range order in the PI phase is assumed. The measured anisotropy of the x-ray absorption spectra is discussed in relation to spin-polarized density functional calculations.Comment: 8 pages, 5 figure

The unusual electronic structure of the "pseudo-ladder" compound CaCu2O3

Experimental and theoretical studies of the unoccupied electronic structure of CaCu2O3 single crystals have been performed using polarization-dependent x-ray absorption spectroscopy and band structure calculations. The measured hole distribution shows an unusual large number of holes in orbitals parallel to the interlayer direction which is in agreement with the theoretical analysis. CaCu2O3 deviates significantly from the standard pd-sigma cuprate picture. The corresponding strong interlayer exchange is responsible for the missing spin gap generic for other two-leg ladder cuprates.Comment: 4 pages, 3 figures include

Crossing borders of material science – a new approach of aerogel preparation for electron microscopy

A new method for the embedding and preparation of organic aerogels for electron mciroscopic Analysis like Crosssectioning, Lamella preparation, FIB-Tomography and Transmissio Electron Microscop

The surface science of quasicrystals

The surfaces of quasicrystals have been extensively studied since about 1990. In this paper we review work on the structure and morphology of clean surfaces, and their electronic and phonon structure. We also describe progress in adsorption and epitaxy studies. The paper is illustrated throughout with examples from the literature. We offer some reflections on the wider impact of this body of work and anticipate areas for future development. (Some figures in this article are in colour only in the electronic version